From: James Smart <jsmart2021@gmail.com>
Date: Tue, 26 Jun 2018 08:24:29 -0700
Subject: [PATCH] scsi: lpfc: devloss timeout race condition caused null
 pointer reference
References: bsc#1102658
Git-commit: b0e830125b669570d8096b8ba22eb00f659fc05e
Patch-mainline: v4.19-rc1

A race condition between the context of devloss timeout handler and I/O
completion caused devloss timeout handler de-referencing pointer that had
been released.

Added the check in lpfc_sli_validate_fcp_iocb() on LPFC_IO_ON_TXCMPLQ to
capture the race condition of I/O completion and devloss timeout handler
attemption for aborting the I/O. Also, added check on lpfc_cmd->rdata
pointer before de-referenceing lpfc_cmd->rdata->pnode.

Also, added protection in lpfc_sli_abort_iocb() routine on driver performed
FCP I/O FLUSHING already under way before proceeding to aborting I/Os.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/scsi/lpfc/lpfc_scsi.c |  5 +++++
 drivers/scsi/lpfc/lpfc_sli.c  | 13 +++++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 72abd5c133cf..8f5ef50dbb4e 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -4538,6 +4538,11 @@ lpfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
 	int err;
 
 	rdata = lpfc_rport_data_from_scsi_device(cmnd->device);
+
+	/* sanity check on references */
+	if (unlikely(!rdata) || unlikely(!rport))
+		goto out_fail_command;
+
 	err = fc_remote_port_chkready(rport);
 	if (err) {
 		cmnd->result = err;
diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 2ad16d89d67e..bbb286c6c94e 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -11097,10 +11097,11 @@ lpfc_sli_validate_fcp_iocb(struct lpfc_iocbq *iocbq, struct lpfc_vport *vport,
 	struct lpfc_scsi_buf *lpfc_cmd;
 	int rc = 1;
 
-	if (!(iocbq->iocb_flag &  LPFC_IO_FCP))
+	if (iocbq->vport != vport)
 		return rc;
 
-	if (iocbq->vport != vport)
+	if (!(iocbq->iocb_flag &  LPFC_IO_FCP) ||
+	    !(iocbq->iocb_flag & LPFC_IO_ON_TXCMPLQ))
 		return rc;
 
 	lpfc_cmd = container_of(iocbq, struct lpfc_scsi_buf, cur_iocbq);
@@ -11110,13 +11111,13 @@ lpfc_sli_validate_fcp_iocb(struct lpfc_iocbq *iocbq, struct lpfc_vport *vport,
 
 	switch (ctx_cmd) {
 	case LPFC_CTX_LUN:
-		if ((lpfc_cmd->rdata->pnode) &&
+		if ((lpfc_cmd->rdata) && (lpfc_cmd->rdata->pnode) &&
 		    (lpfc_cmd->rdata->pnode->nlp_sid == tgt_id) &&
 		    (scsilun_to_int(&lpfc_cmd->fcp_cmnd->fcp_lun) == lun_id))
 			rc = 0;
 		break;
 	case LPFC_CTX_TGT:
-		if ((lpfc_cmd->rdata->pnode) &&
+		if ((lpfc_cmd->rdata) && (lpfc_cmd->rdata->pnode) &&
 		    (lpfc_cmd->rdata->pnode->nlp_sid == tgt_id))
 			rc = 0;
 		break;
@@ -11231,6 +11232,10 @@ lpfc_sli_abort_iocb(struct lpfc_vport *vport, struct lpfc_sli_ring *pring,
 	int errcnt = 0, ret_val = 0;
 	int i;
 
+	/* all I/Os are in process of being flushed */
+	if (phba->hba_flag & HBA_FCP_IOQ_FLUSH)
+		return errcnt;
+
 	for (i = 1; i <= phba->sli.last_iotag; i++) {
 		iocbq = phba->sli.iocbq_lookup[i];
 
-- 
2.12.3